期刊
GENERAL AND COMPARATIVE ENDOCRINOLOGY
卷 173, 期 2, 页码 323-332出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.ygcen.2011.06.001
关键词
Stress; Corticosterone; Neonate; Passerine; Predation; Anthropogenic disturbance
资金
- Animal Behaviour Society
- Montana Integrative Learning Experience for Students
Roads have been associated with decreased reproductive success and biodiversity in avian communities and increased physiological stress in adult birds. Alternatively, roads may also increase food availability and reduce predator pressure. Previous studies have focused on adult birds, but nestlings may also be susceptible to the detrimental impacts of roads. We examined the effects of proximity to a road on nestling glucocorticoid activity and growth in the mountain white-crowned sparrow (Zonotrichia leucophrys oriantha). Additionally, we examined several possible indirect factors that may influence nestling corticosterone (CURT) activity secretion in relation to roads. These indirect effects include parental CURT activity, nest-site characteristics, and parental provisioning. And finally, we assessed possible fitness consequences of roads through measures of fledging success. Nestlings near roads had increased CURT activity, elevated at both baseline and stress-induced levels. Surprisingly, these nestlings were also bigger. Generally, greater corticosterone activity is associated with reduced growth. However, the hypothalamic-pituitary-adrenal axis matures through the nestling period (as nestlings get larger, HPA-activation is greater). Although much of the variance in CURT responses was explained by body size, nestling CURT responses were higher close to roads after controlling for developmental differences. Indirect effects of roads may be mediated through paternal care. Nestling CURT responses were correlated with paternal CURT responses and paternal provisioning increased near roads. Hence, nestlings near roads may be larger due to increased paternal attentiveness. And finally, nest predation was higher for nests close to the road. Roads have apparent costs for white-crowned sparrow nestlings - increased predation, and apparent benefits - increased size. The elevation in CURT activity seems to reflect both increased size (benefit) and elevation due to road proximity (cost). Whether or not roads are good or bad for nestlings remains equivocal. However, it is clear that roads affect nestlings; how or if these effects influence adult survival or reproduction remains to be elucidated. (C) 2011 Elsevier Inc. All rights reserved.
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